Clinical phenotype and cytokine profile of adult IgA vasculitis with joint involvement

Objective Joint involvement can be observed during the course of adult IgA vasculitis (IgAV). However, clinical picture, prognosis, or pathophysiological data associated with this condition have been overlooked. We aimed to describe the clinical characteristics and outcome of IgAV patients with joint involvement and look to a specific cytokine profile. Methods We analyzed clinical and biological data from a nationwide study that included adult IgAV patients. Presentation and outcomes of patients with or without joint involvement were compared at baseline and during follow-up. Plasma cytokine measurements of IgAV patients included in a prospective study were also analyzed using multiplex assays. Results Among 260 patients, 62% had joint involvement. Among them, rheumatological manifestations included arthralgia (100%) or arthritis (16%), mostly involving the knees and ankles. In multivariate analysis, patients with joint involvement, compared to those without, were younger (p = 0.002; OR 0.87; 95% CI 0.80-0.95) and showed more frequent gastrointestinal tract involvement (p = 0.012; OR= 2.08; 95% CI 1.18-3.67). However, no difference in terms of clinical response, relapse, end-stage renal disease, or death was observed between groups. Among 13 cytokines measured, plasma interleukin (IL)-1 beta level was higher in patients with joint involvement compared to those without (mean +/- SEM IL-1 beta, 3.5 +/- 1.2 vs. 0.47 +/- 0.1 pg/ ml; p = 0.024) or healthy controls (vs. 1.2 +/- 0.5 pg/ml; p = 0.076). Conclusion Joint involvement is frequent in adult IgAV and is associated with more frequent gastrointestinal involvement. Increased plasma IL-1 beta levels raise the question of targeting this cytokine in patients with chronic and/or refractory joint involvement.

Automated summary

Joint involvement is frequent in adult IgA vasculitis and is associated with more frequent gastrointestinal involvement. Increased plasma interleukin-1 beta levels in patients with joint involvement suggest a potential target for therapy targeting this cytokine in chronic and/or refractory cases.